1. Field of the Invention
The present invention relates to agricultural harvesters such as combines, and, more particularly, to crop residue systems used in such combines.
2. Description of the Related Art
An agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves and performs a threshing operation on the crop to remove the grain. Once the grain is threshed, it falls through perforations in the concaves onto a grain pan. From the grain pan, the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. A cleaning fan blows air through the sieves to discharge straw, chaff and other debris toward the rear of the combine.
During the process of harvesting, crop material other than grain (MOG) is intended to be expelled from the combine. This material is usually derived from one of two areas, the threshing rotor or the cleaning system. The material expelled from the threshing rotor is generally referred to as straw and the material expelled from the cleaning system is generally referred to as chaff. This crop residue can be dealt with in several ways, generally categorized as spread and windrowed.
Spread refers to using a mechanical device to distribute the straw and/or chaff evenly across the width of the combine header cut width. This spread material is usually chopped to as short a length as possible so that when it is spread it will break down as quickly as possible and not interfere with tillage or seeding operations.
Windrowing refers to the process of dropping straw directly behind the combine in a continuous stream. The purpose of doing this is usually to allow post harvest processing of the straw such as shaping it into bales. In this process, the straw is usually allowed to pass through the combine with as little interference as possible so that it remains as close as possible to its original length and condition.
Many harvester systems have two separate spreading systems, one of which is dedicated to spreading the chaff from the cleaning system and another dedicated to spreading the straw from the rotor. These systems can be operated independent of one another. Currently, in order to windrow straw discharged from the rotor, the spreader disks normally used to spread the crop residue, must be removed from the machine and stored elsewhere since there is little available storage on the combine. Besides having to remove the disks, there is an absence of a device to slow the velocity of the straw before it hits the ground. This causes the straw to be driven into the stubble and makes it very difficult to return and pick up later. While windrowing straw, many operators prefer to spread chaff from the cleaning system which requires the use of a secondary spreader on the machine.
It has been proposed in co-pending application entitled “System for Flexible Crop Residue Management” of common assignment with the present invention to provide the ability to windrow straw and spread chaff. In that application, a windrow chute is displaceable between several positions in coordination with displacement of a swath door for the crop residue stream. The implementation of the coordinated displacement can be difficult and complicated.
Accordingly what is needed in the art is a linkage for a crop residue management system that is simple and effective.